The present invention generally relates to a magnetic recording/reproducing apparatus, and particularly to a magnetic recording/reproducing apparatus not only capable of performing a recording and reproducing on and from a magnetic tape contained in a standard size tape cassette but also capable of performing a recording and reproducing on and from a magnetic tape contained in a compact size tape cassette.
Currently, a standard size tape cassette and a compact size tape cassette are used in a magnetic recording/reproducing apparatus such as a home video tape recorder. The standard size tape cassette and the compact size tape cassette have different dimensions. Particularly, the compact size tape cassette is used widely in a portable video tape recorder combined with a television camera. As the conventional home video tape recorders are designed to play the standard size tape cassette, the conventional video tape recorder cannot play the compact size tape cassette without using an adapter having a size identical to the size of the standard size tape cassette for accommodating the compact size tape cassette.
However, the use of such a separate adapter requires a loading operation of two steps, first for loading the compact size tape cassette on the adapter and then loading the adapter on the video tape recorder. Such a two step loading operation makes the loading operation performed by the user of the video tape recorder complex. Further, the use of the adapter adds an extra expense to the video tape recorder. Therefore, there is a demand for a video tape recorder equipped with a tape cassette loading system which can load both the standard size tape cassette and the compact size tape cassette without using a separate adapter.
According to the Laid-open Japanese Patent Application No. 54069/1986, a tape cassette loading system is known in which two different types of tape cassettes having different sizes can be loaded in a video tape recorder. The tape cassette loading system of this prior art is constructed such that reel disks for driving a supply reel and a take up reel of a loaded tape cassette are engaged with the respective reels directly when the standard size tape cassette is loaded and when the compact size tape cassette is loaded. However, the compact size tape cassette commonly available in the market has such a construction that the take up reel is driven by a gear engaged with a tooth formed on a periphery of a lower flange of the take up reel. Therefore, such a tape cassette cannot be used in the tape cassette loading system as disclosed in the aforementioned prior art.
Generally, the tape cassette is held on the video tape recorder at a predetermined position by engagement with a plurality of positioning pins provided on the tape cassette loading system of the video tape recorder. As the location of the portions of the tape cassette to be engaged with the positioning pins for the standard size tape cassette is different from that of the compact size tape cassette, the tape cassette loading system has to be able to change the location of the positioning pins on the tape cassette loading system depending on the type of the tape cassette to be loaded. The aforementioned prior art tape cassette loading system has a construction in which the movement of the reel disk responsive to the type of the tape cassette and the movement of the positioning pins responsive to the type of the tape cassette are made separately. Thus, the prior art tape cassette loading system has a further problem in that the predetermined relationship in the position of the reel disk and the positioning pins may be lost as a result of the movement of the reel disks and the positioning pins.
Further, there is proposed a tape cassette loading system in which a separate sub-chassis is used for carrying a drive gear for driving the take up reel of the compact size tape cassette, an intervening gear member for meshing with the drive gear and further meshing with the reel disk for the take up reel of the standard size tape cassette, and a plurality of positioning pins for engagement with the compact size tape cassette for positioning are carried separately from a main chassis which carries the reel disks for engagement with the take up reel and the supply reel of the standard size tape cassette together with a plurality of positioning pins for positioning the standard size tape cassette. In this construction, the sub-chassis is moved up and down responsive to the type of the tape cassette to be played. Thus, when the compact size tape cassette is to be played, the sub-chassis is raised and the intervening gear member for meshing with the drive gear of the take up reel of the compact size tape cassette is engaged with the reel disk for the take up reel on the main chassis. On the other hand, when playing the standard size tape cassette, the sub-chassis is lowered and the drive gear for the take up reel of the compact size tape cassette is disengaged from the reel disk for driving the supply reel of the standard size tape cassette. Thereby, the drive gear is also disengaged from the standard size tape cassette.
In this construction, there is a problem that the engagement of the intervening gear member with corresponding teeth on the reel disk referred to hereinafter as a reel gear member may cause a jamming when the sub-chassis is simply raised or lowered in the vertical direction relative to the main chassis. In the worst case, the sub-chassis becomes immovable up and down as a result of the jamming. Further, it is desired in the aforementioned construction that the reel disk on the main chassis for driving the take up reel of the standard size tape cassette be not rotated during the movement of the sub-chassis in the upward direction so as to avoid excessive stretching or slackening of the magnetic tape in the tape cassette. On the other hand, from the viewpoint of the engagement of the intervening gear member and the reel gear member, it is necessary that the reel gear be freely rotatable in order to achieve a smooth engagement of the intervening gear member and the reel gear member.
In general, it is necessary to apply or release a brake to or from the reel disk with a suitable timing whatever the type of the used tape cassette may be. The braking of the reel disk is usually performed by driving a braking mechanism provided on the reel disk by using a main gear which drives the tape cassette loading system. In the case of the tape cassette loading system as disclosed in the aforementioned Laid-open Japanese Patent Application No. 54069/1986, the braking mechanism also must be moved responsive to the movement of the reel disk. Further, the mechanism used for driving the braking mechanism should be switched responsive to the type of the tape cassette. As a result, the tape cassette loading system in such a prior art becomes inevitably complex and the size of the video tape recorder is increased.